When police opened Cohen's backpack at around 11 p.m. at Alcosta Boulevard at Davona Drive, they discovered a "homemade destructive device," according to the newspaper. In other words: they found a bomb in the bicyclist's backpack.

The Walnut Creek bomb squad was summoned and disposed of the explosive, and Cohen, who is described as a resident of San Ramon and Dublin, was booked into Contra Costa County Jail in Martinez.